This invention relates to a high precision replication system for forming high fidelity replications of a master substrate surface.
The use of a highly polished lenses and mirrors is essential in some high technology systems, such as optical systems and solar panels. For example, in telescopes and microscopes, the efficiency of the optical system depends on the precision of the lens or mirror used in the optics. An imperfect surface leads to light loss due to reflection, and inaccuracies from interference due to uncontrolled refraction.
Similarly, a well polished transparent surface for a solar panel is important for high efficiency. A well polished surface transmits more light with less light loss than does an unpolished, rough surface. For applications such as solar panels for spacecraft, it is extremely important that highly polished, smooth solar panels be used to maximize the energy available to the satellite.
Other applications where highly polished surfaces are useful include sun sensors or star sensors used in spacecraft applications, because a highly polished surface has less reflection of light than a rough surface.
Rather than individually fabricating highly polished surfaces, techniques have been developed to replicate a master surface. Because the cost of labor needed to polish individual lenses or mirrors is extremely high, replication is a cost-effective technique to produce large quantities of very smooth surfaces. Typical of prior art replication systems are those described in U.S. Pat. Nos. 4,235,654 and 5,160,668 (polymer polymerization on a substrate), 5,175,929 (chemical vapor deposition), and 5,296,178 (spraying a high melting point metal). However, typical replication systems typically add defects to a replicand not present in the master. The best replication systems now are able to produce replicands with an RMS smoothness only within 10 to 20 Angstroms of the masters, when the masters have an RMS smoothness of less than 100 Angstroms.
Other disadvantages of conventional replication systems are they can be time-consuming and expensive to use. Another disadvantage of current replication systems is the replicands produced can be relatively thick and heavy. Also, the replicands typically have an RMS smoothness only within 5 to about 20 Angstroms of the masters, which can represent more than 20% error, often time-consuming and expensive polishing is necessary.
For the foregoing reasons, there exists a need for a high precision replication system which can produce replicands close to the smoothness of the master, and preferably with an RMS smoothness within 10 Angstroms of the master when the master has an RMS smoothness of less than 100 Angstroms. In addition, it is preferred that such a system produce low cost and lightweight replicands.